Interpretive Summary: In an earlier work, dust samples on PVC filters were produced by an elaborate cotton blending and dust collection protocol. The dust samples produced were 'uniform', vertically elutriated dust samples. The dust samples were used in a two part endotoxin assay study between different laboratories. The results from the study prompted the need for further study which required additional dust samples on filters. We collected a second series of dust samples to be used for further endotoxin assay studies. The samples were collected on two types of filters using 'three sources of cotton' for the dust. This paper describes the cotton blending procedure and the dust collection process, and also a description of the dust sample population.

Technical Abstract:
Previously, an elaborate cotton blending and dust collection protocol was developed and implemented to produce 'uniform', vertically elutriated dust samples which was used in a two part interlaboratory endotoxin assay study. The results generated interest in continuing further study. To satisfy this need, a second series of dust samples on two types of filters were produced from 'three sources of cotton'. A description of the cotton blending and dust collection process will be presented as well as a description of the dust samples collected.